A cytological study of parotid basal cell adenoma

Abstract

Objective : We retrospectively evaluated cytological features of parotid gland basal cell adenoma.
Study Design : Material consisted of 7 cytological specimens—5 fine-needle aspirations (FNA) and 2 imprint stamps—histologically confirmed as parotid basal cell adenoma.
Results : Tumor cells were tightly cohesive and formed different-sized clusters. Individual cells were small and isomorphic with a high N/C ratio. Nuclei were oval or short and spindle-shaped. Of the 7 specimens, 3 showed peripheral palisading and 4 basement-membrane-like materials. Four also showed stromal-cell-like spindle-shaped cell clusters near cohesive tumor cell clusters and immunohistochemical positivity for S-100 protein. Stromal mucin was not seen in the background.
Conclusion : Cytologically, the presence of S-100 protein-positive stromal-cell-like spindle-shaped cell clusters near cohesive tumor cell clusters appears to be a diagnostic clue indicating basal cell adenoma.